1. Field of the Invention
The present invention relates to an anatomical prosthesis for the repair of hernias, and in particular a prosthesis adapted for the repair of inguinal hernias by laparoscopy.
2. Description of the Related Art
In a general manner, prostheses for the repair of the inguinal region and for the treatment of hernias are well known, and consist in particular of one or more porous prosthetic plates, made of a biocompatible synthetic material, which may or may not be absorbable, for example polyethylene, polypropylene, polyester, or similar, optionally having undergone a surface treatment to render it biocompatible with the cellular medium in which they are implanted.
These prostheses can be obtained, for example, by joining together two plates of prosthetic material by knitting. Such a prosthesis has been described in the American patent U.S. Pat. No. 4,769,038, granted to Bendavid et al., this prosthesis being designed essentially for the complete reconstruction of the inguinal region. In accordance with this patent, the prosthesis comprises a first plate, being a substantially plane upper plate, and a second plate, being a lower plate, the plates each comprising a porous and flexible prosthetic material. These plates of generally elongate shape are connected to one another along a straight connection line by a connection means, for example a seam. The prosthesis additionally comprises a third plate which is connected to the two others along the same straight connection line, and by the same seam.
When repair of a hernia in the inguinal region is being performed by a posterior and extraperitoneal laparoscopic route, it is very important to be able to locate, and to cover with the prosthesis, certain anatomical elements of the anterior wall of the abdomen, which elements may be described as follows, from the inside outwards, and for the right-hand side of the body:
to the inside, the anterior retro-parietal space is limited towards the front by the rectus abdominis muscles, towards the rear by the peritoneum, and underneath by the upper edge of the os pubis; PA1 the middle part is limited towards the front by the fascia transversalis, and the conjoint tendon, with the iliac vessels below, and with the transverse muscle above; PA1 in the outer part, towards the front there is the internal orifice of the inguinal canal with the elements of the spermatic cord (spermatic vessels and ductus deferens), with the psoas muscle below, and with the transverse muscle above.
In summary, and this constitutes the starting point of the present invention, it is noted that the inguinal region is particular in that the elements described hereinabove are not all in the same spatial plane, but are disposed in an oblique arrangement from the top downwards, and from the outside inwards. In the case of an inguinal hernia, the prosthesis implanted after reduction of the hernia must ensure satisfactory covering by adapting to the contours of the region and by respecting the obliqueness of the inguinal space, if possible without leaving any empty spaces.
This requirement poses a considerable problem when using the known prostheses, since none of these is really adapted to the anatomy of the site of the surgical intervention, a fact which compels the surgeon to cut the prosthesis, often several times, in order to obtain a prosthesis which is more or less well suited. Now, a poor covering of the anatomical elements described hereinabove is probably one of the main causes of recurrence of hernias, and such hernias may be even more difficult to treat because of the deterioration of the anatomical structures which has been provoked by the earlier hernia.